Polysiloxane copolymers derived from the carborane-silicon phthalocyanine monomer

ABSTRACT

Polysiloxane copolymers derived from the carborane - silicon phthalocyanine monomer. Said copolymers are useful as high temperature stable coatings, adhesives, molding compounds, for electronic components and laminating resins.

United States Patent Barnes et al.

[ 51 June 20, 1972 [54] POLYSILOXANE COPOLYMERS DERIVED FROM THECARBORANE- SILICON PHTHALOCYANINE MONOMER [72] Inventors: Robert L.Barnes, Clifton, NJ.; William M. Block, Staten Island, N.Y.; DanielGrafstein, Morristown, NJ.

[52] U.S.Cl ..260/46.5E,1l7/135.1, 161/93, 161/193, 260/2 S, 260/33.6SB, 260/37 SB,

[51] Int. Cl. ..C081 11/04 [58] Field of Search 260/2 Sl, 46.5 E, 448.2N

[56] References Cited UNITED sTATEs PATENTS 3,094,536 6/1963 Kenney eta1. ..260/3l4.5

OTHER PUBLlCATlONS McGregor, Silicones And Their Uses, pg. 3 l 32, 226and 227, I954, McGraw- Hill Book Co., NY.

Primary Examiner-Donald E. Czaja Assistant Examiner-M. l. MarquisAttorney-S. A. Giarratana and S. Michael Bender [57] ABSTRACTPolysiloxane copolymers derived from the carborane siliconphthalocyanine monomer. Said copolymers are useful as high temperaturestable coatings, adhesives, molding compounds, for electronic componentsand laminating resins.

1 Claim, No Drawings POLYSILOXANE COPOLYMERS DERIVED FROMCARBORANE-SILICON PI-lTI-IALOCYANINE MONOMER This application is acontinuation-in-part of copending application Serial No. 619,199, filedFeb. 28, 1967 now abandoned.

The invention herein described was made in the course of or under acontract or subcontract thereunder, with the Department of the Navy.

BACKGROUND OF THE INVENTION DESCRIPTION OF THE PRIOR ART Siliconphthalocyanines, previously described by .Kenney et al., in their U.S.Pat. No. 3,094,536 are characterized by a silicon atom centrally locatedwithin a phthalocyanine nucleus. In these compounds, silicon hashexacoordinate character which distinguishes it from the moreconventional silicon compounds in which the silicon atom has tetrahedralcharacter. The extraordinary thermal, chemical and oxidative stabilityof the silicon phthalocyanines is attributed to the hexacoordinatecharacter of silicon in these compounds. Dichlorosilicon phthalocyanineis used as a reactant for the preparation of the prepolymer which is thesubject of this invention. This compound can be written as PcSiCl wherePc represents the phthalocyanine ring (C H N As described by Kenney, the4 isoindole units of the phthalocyanine ring are linked through thenitrogen atoms to the central metal atom in a square planar ring. Themetal participates in bonding to two chlorine atoms perpendicular to andon either side of the planar ring.

Kroenke and co-workers prepared siloxane polymers from dichlorosiliconphthalocyanine (lno'rg. Chem,2,l964-(l963) Hydrolysis of dichlorosiliconphthalocyanine to dihydroxysilicon phthalocyanine and subsequentdehydration of the dihydroxy compound gave a siloxane polymer as shownbelow.

1120 Heat PcSiClr PcSi(OH)z v (PcSiO),

In this polymer, the phthalocyanine rings are stacked in carddeck"fashion with the SiOSi and OSiO linkages being linear. No decompositionof the polymer was detected when it was subjected to a temperature of520 C. The polymer was also very resistant to chemical attack. Althoughthis polymer exhibits excellent chemical and thermal stability, itsphysical properties render it virtually useless for any application. Itis a non-melting blue powder which is insoluble in all common organicsolvents.

Others have attempted to modify the silicon phthalocyanine structure inorder to prepare materials having useful characteristics (ex. solubilityin common organic solvents). Kenney and coworkers in the above-mentionedU.S. Pat. No. 3,094,536 reported the reaction of both dihydroxysiliconphthalocyanine and dichlorosilicon phthalocyanine with benzyl alcohol togive dibenzoxysilicon phthalocyanine. This process showed the reactivityof both the silicon hydroxy group and a silicon chlorine group in ahexacoordinate structure with the hydroxyl group of an alcohol. However,the final product lacked reactive groups for further polymer formation.Luloff and co-workers attempted to prepare a prepolymer condensationproduct from the reaction of dihydroxysilicon phthalocyanine withresorcinol (Final report NObs 90l94, Nov. 15, I964, General PrecisionSystems, Inc). The objecw ,tive of this work was to prepare a prepolymerhaving residual reactive groups. The prepolymer could then be furtherpolymerized or reacted with a third comonomer andthereby incorporatedinto apolymer backbone. The compound they hoped to form wasHO-OO-SHPcF-O-OQH Although they do report infrared spectral evidence forsome reaction, no evidence was provided to indicate that the productmixture was characterized or that the objective was realized.

The lack of any prior success in incorporating a silicon phthalocyaninegroup into a prepolymer with residual functional groups can beattributed to several possible factors. When PcSiCl or l cSi(Ol*.l) arereacted with a difunctional comonomer such resorcinal, there is a greattendency for long-chain polymer formation to occur. In addition, HCl orby-products, if not removed from the system, could destroy theSilicon-Oxygen-Organic linkage. -On the other hand, the extremeinsolubility of the phthalocyanine monomer may have been responsible fora low degree of polymerization as well as the complete intractibility ofthe products obtained from all reported att mpts to synthesize usefulpolymeric materials. Therefore, it is not surprising that .a usefulprepolymer was not isolated.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Each of the problems enumeratedabove has been overcome as illustrated-by the subject invention. Wehavefound that by judicious choice of coreactant and reactionconditions, a prepolymer containing the silicon phthalocyanine group canbe easily formed in high yield. This prepolymer is soluble in commonorganic solvents and contains reactive groups through which it can beincorporated into a variety of polymer structures forming an integralpart of the polymer backbone.

The coreactant for the preparation of this prepolymer contains acarborane nucleus. Carboranes are a rather new series of higher boranederivatives and are described in Kirk- Othmer's Encyclopedia of ChemicalTechnology" Vol. 3, pages 698, 699. As stated therein: The B C l-lmolecule contains a cage structure very similar to and isoelectronicwith the regular icosahedron of the B l'hf anion. It is characterized byremarkable stability and low reactivity toward oxidizing and reducingreagents. Carboranes exist in three clovo isomer forms (ortho, meta andpara) depending on the position of the carbon atoms. In general, theisomers have the same chemical properties and undergo similar chemicalreactions. The structures are unusually chemically inert, and standardorganic reactions can be performed on organofunctional substituentsattached to the carbon atoms:

meta D. Grafstein and .l. Dvorak, Inorg. Chem., 2, l l28 para S. Papettiand T. Heying, J. Am. Chem. Soc., 86,

ortho T.Heying,et al., Inorg. Chem, 2, I089 (1963) and M. Fein,et al.,Inorg. Chem, 2, llll (I963).

In accordance with the present invention, dichlorosilicon phthalocyanineand a carborane moiety [bis( hydroxymethyl)- ortho-carborane] arereacted to give bis(hydroxymethylortho-carboranylmethyloxy) siliconphthalocyanine (also called the 2:l prepolymer) according to thefollowing equation.

is the ortho carborane moiety and Si(C32Hi6Na). is the siliconphthalocyanine moiety, and the formula (Ca2H|sNa)Sicl2 refers to asilicon phthalocyanine moiety connected to two chlorine atoms at thecentral silicon atom.

The reaction is performed in refluxing toluene while maintaining a flowof nitrogen gas through the solution to remove by-product hydrogenchloride. The product is completely The bis(hydroxymethyl-ortho-carboranylmethyloxy) silicon phthalocyanineprepolymer can be incorporated into polysiloxane and polyurethanestructures by conventional techniques. Polysiloxanes and polyurethanesare commonly used as adhesives, laminating resins and molding compounds.

The preparation of these materials and examples of their application aregiven below.

Polysiloxane copolymers can be synthesized from the condensation ofbis)hydroxymethyl-ortho-carboranylmethyloxy)silicon-phthalocyanine withdimethyldichlorosilane. methylphenyldichlorosilane,methyltrichlorosilane and similar alkyl and urylhalosilanes. Polymers ofthe following general soluble in the solvent under the conditions of thereaction and formula were synthesized.

BmHro reactants as illustrated. 20 where R, and R can be an alkyl, aryl,or hydroxyl group provided no more than one hydroxyl group be pendant tothe silicon atom and x can be as high as 14; n represents the number ofrepeating units in the chain. Examples of polymers which have beenprepared are given in Table I.

can easily be separated from excess below. Conversions of 92 percent areroutinely obtained. This reaction is quite novel in view of the failureof others to incorporate a silicon phthalocyanine group into a usefulpolymer or prepolymer structure.

TABLE 1.PROPERTIES OF SILOXANE POLYMERS CONTAINING 2:1?

Flow point, Percent Repeating unit Description C. 2:1P I- ICH: /CH@ ISoftgum 70-80 .47-60 2:1P0-S iO-S i-0 L Me. Al. CH /cm Soft, verybrittle, glassy solid- 7os0 as -2;1P0-s xi-0-si0 L \Hs /x \('!3H=CH2/yJu lo.Ht\ I -..do .Q. 40-50 55 2:1PO-E'i0- L lcHs in Medium 7080 50 L. Aie Polyurethane copolymers can be generated by the condensation ofbis(hydroxymethylcarboranylmethyloxy)silicon phthalocyanine with organicdiisocyanates such as toluene diisocyanate andmethylenebis-(p-phenylisocyanate). Thus. copolymers possessing thefollowing nominal formula were prepared.

where R can be any alkyl or aryl difunctional group. u again 60represents the number of repeating units in the chain.

Several such compounds are shown below.

and

HoCH CB fl CCH- OH where CB H C is the meta carborane nucleus.

I NH -OCHzC- /CCHgOSl(PC)OCHiCwCCHZO 0 O B OH U 13 011 0 B mlIm Thepolymers herein described are useful as high temperature stable coatingsand adhesives, molding compounds for electronic components andlaminating resins. The special properties of the phthalocyaninestructure, particularly its intense blue color, and its high chemicaland thermal stability, can be employed to generate permanent, intenselyblue coatings and plastics without the addition of colorants. I

In order to more fully understand the present invention, the followingspecific examples are given by way of illustration: Example 1 Synthesisof bis( hydroxymethyl-ortho-carboranylmethyloxy) silicon phthalocyanine(2: l Prepolymer) A S-liter three-neck reaction flask was charged with17.0 g of dichlorosilicon phthalocyanine, 39.2 g ofl,2-bis(hydroxymethyl)-ortho-carborane and 4.2 liters of toluene. Theflask, was equipped with a reflux condenser, mechanical stirrer andthermometer-gas inlet combination. A nitrogen gas flow was; maintainedthrough the solution during the reaction period. The mixture was heatedto reflux and held at that temperature for 5 hours. After the flaskcooled to 100 C., the mixture was filtered through a Biichner funnelusing No. 42 filter paper. Distillation of the bulk of the solvent fromthe filtrate, followed by Rinco evaporation to dryness, gave a solidconsisting of desired product and unreacted 1,2-bis(hydroxymethyl)-ortho-carborane. The solid mixture, air-dried at about 85 C. with a heatlamp, was successively treated with 1,000 ml and 500 ml portions ofmethanol. The insoluble 2:l prepolymer (26. lg) was air-dried as above.This amount represents a conversion of 92 percent based on chargeddichlorosilicon phthalocyanine. The elemental analysis of the solid isgiven below;

Calculated: C, 50.70; H, 4.89; N, 11.83; B, 22.84; Cl, 0

2:1 Prepolymer Found: C, 50.05; H, 4.98; N, 11.87; B, 22.73; Cl, 0.16.Example ll Synthesis of polysiloxane copolymers from condensation ofbis(hydroxymethyl-ortho-carboranylmethyloxy) silicon phthalocyanine withdimethyldichlorosilane, etc.

A solution of 25.0 ml of dimethyldichlorosilane and 20.0g ofbis(hydroxymethyl-ortho-carboranylmethyloxy) silicon phthalyocyanine in600 ml of pyridine (previously distilled from BaO) was prepared under anitrogen atmosphere. The solution, along with a magnetic stirring bar,was placed in a one-liter round-bottom single-neck flask, and the flaskwas sealed. The contents of the flask were stirred for one hour atambient temperature, after which 1 1.1 ml of methyltrichlorosilane wasadded with stirring. Five minutes later, 8 ml. of water was addeddropwise from a funnel over a period of minutes. The reaction mixturewas stirred for an additional minutes.

in order to isolate the polymer, the pyridine solution was divided inhalf and each half was mixed with 1.5 liters of benzene to precipitatethe pyridine hydrochloride. Afier gravity filtration to remove theprecipitate, the filtrates were combined and then split into three equalvolume fractions, Each fraction was washed five times with 500 ml ofwater. The washed fractions were dried for one-half hour over a 50 3.quantity of MgSO The solutions were combined and evaporated to drynesson a Rinco rotary evaporator to yield ,a

resin which could be applied as described in Example 111. Example 111Methods for preparing adhesives, coatings and glass-cloth-laminates withthe polymer described in Example 11 A toluene solution of the polymer(described in Example ll) consisting of 75 percent by weight of thepolymer and 25 percent by weight of toluene was prepared. The solutionwas dipcoated on copper and steel substrates, dried for one hour at roomtemperature and then cured at 200 C. for 2 hours. Coatings of 5 milthickness which had high gloss and adhesion were obtained. Thesecoatings resisted crazing at 300 C. for up to 4 hours. The addition of15 parts of pyrogenic alumina to parts of resin was found to reducebrittleness of the cured coatings. Coatings on glass cloth, cured in themanner described above, resisted crazing up to 15 hours at 200 C.Laminates could be prepared in the following manner. Seven plies ofglass cloth, dipped in the polymertoluene solution and dried, werestacked in a Carver Press and pressed at 50 psi and 100 C. to give alaminate structure. Example lV Synthesis of polyurethane copolymers fromcondensation of bis(hydroxymethyl-ortho-carboranylmethyloxy) siliconphthalocyanine with isocyanates Five grams (0.0063 moles) ofbis(hyroxymethyl-ortho-carboranylmethyloxy) silicon phthalocyanine wasadded to 10 grams of a 50 percent solution ofmethylenebis-(p-phenylisocyanate) in chlorobenzene (0.02 moles ofreagent). One drop of triethylamine was added, and the reaction mixturewas gently warmed for several minutes. The temperature continued to riseto the boiling point of the chlorobenzene with no external aidindicating that reaction had taken place. BHMC,

(1,2-bis(hydroxy-methyl-o-carborane)(5 gm, 0.025 moles) was then addedto the cooled viscous mass. Polymerization took place immediately, andthe reaction mixture'set up with evolution of heat before all of theBHMC had reacted, as indicated by the presence of white granules in theresin ball. The plastic reaction mass was added to 750 ml. of acetone,stirred for 15 minutes and filtered. Removal of solvent from thewashings left a brittle glassy residue which was saved for furtherinvestigation. The solid residue in the funnel was washed with another100 ml. of acetone. Example V Technique for molding the polymerdescribed in Example IV.

The polymer described in Example IV was vacuum dried for 3 hours at 80C. to give a hard solid. The dried material was hand ground in a mortarand pestle and pressed into a oneinch disc at C. and 4,000 psi. The dischad a smooth shiny surface that was not abraded by scratching with asharp instrument. It had good impact strength and retained structuralintegrity up to 250 C.

What is claimed is:

1. Polysiloxane of the following type having at least one phthalocyanineradical in the repeating units:

